Technical Abstract:
Vast quantities of cotton gin byproducts (CGB), also known as cotton gin trash or cotton gin waste, are being produced across the cotton belt of the United States annually. Similarly, guayule wastes after rubber latex production, also known as guayule bagasse (GB), is expected to increase as this industry begins to expand. Use of these waste materials in value-added products can help the economics of the crops, and importantly, aid in alleviating waste management and environmental problems. Conventional wood preservatives used to protect wood from insect and microbial damage are presently of major concern to human health and the environment. Finding alternative and economical preservatives is of interest to manufactures of composite building materials. The objectives of this research were to evaluate the physical properties and termite resistance of experimental composition boards made from CGB and GB. Composition boards were made from five different ratios of CGB and GB: 100:0, 75:25, 50:50, 25:75, and 0:100 (C100, C75G25, C50G50, C25G75, and G100). Board composition was homogenous with no orientation of fibers. In addition, three-layered boards (3-layer) consisting of 25% GB (upper layer), 50% CGB (middle layer), and 25% GB (bottom layer) were made. For comparison, a commercial southern pine lumber (SPL) board, a commercial oriented strandboard (OSB), and a commercial preservative treated medium density fiberboard (MDF) were included in the testing. In addition to the termite testing, mechanical properties of the CGB and GB composition boards were measured and compared with various standards of other commercial boards. Five specimens (1.1cm thick x 2.5cm x 2.5cm) were cut from each of the nine different board materials and tested using Eastern subterranean termites. More than 400 active termites were placed into a specimen bottle consisting of sand and the material block to be tested. Weight loss, termite survival days, and visual grade of each specimen at the end of the test were determined. The approximate termite mortality in each bottle after one week was estimated according to the testing standards. Test results confirmed good termite control quality of boards made from GB alone. Boards containing CGB to guayule wastes ratios of 75:25 and 50:50 obtained similar termite resistance to that of the commercial OSB based on the average values of total weight loss and one-week termite mortality rate. In visual grading of tested specimens after the test, all six CGB and GB composition boards and the treated MDF showed better than average rating compared with the commercial OSB and SPL. No difference was found among the average total termite surviving days for all six groups of boards made from CGB and GB. Overall, the biobased CGB and GB boards showed some potential. Results indicate the CGB possesses some inheritable quality of termite resistance.